Telephone mouthpiece attachment



Sept. 17, 1957 H. JUNGHANS 2,806,906

' TELEPHONE MOUTHPIECE ATTACHMENT 2 Sheng-smet 1 Filed De; 4, 1953 l1.7i., 195']` H. JUNGHANS v 2,806,906

TELEPHONE MOUTHPIECE ATTACHMENT Filednec. 4,1953 l 2 sheets-sheet 2 HELM/r n/l//VG HAMS' United States Patent 2,896,906 TELEPHONE MonrrnlncnATTACHMENT Helmut Junghans, Schramberg-Sulgen, Eekenhof, GermanyApplication December 4, 1953, Serial No. 396,271

Claims priority, application Germany December 13, 1952 6 Ciaims. (Cl.179-188) The present invention relates to a telephone apparatus, thecup-shaped mouthpiece of which can be placed against the mouth of theperson, so that the space above the microphone is hermetically sealed tothe mouth of the person.

Such a construction offers the following advantages: An unauthorizedperson cannot overhear the telephone conversation. If there are morepersons present in the room, as for instance in an office room, theconversation will not cause annoyance to other persons working nearby.The invention furthermore offers better facilities for conversation in aroom where noise is present as for example, when a telephone call ismade from an automobile, an aircraft, a railway compartment or the like.

If under such circumstances the cup-shaped mouthpiece is placed againstthe mouth, air is dammed up in the small, closed cup space during theconversation due to the hermetic sealing and the sound is reflected fromthe inside walls of the cup, whereby reproduction of speech is more orless distorted or the voice is altered.

The present invention eliminates these disadvantages. Itis therefore anobject of the invention to provide a structure in which an insertelement merging at its upper end into the mouthpiece is not a plainsurface, but the part to be inserted in the casing containing the valvesand microphone is perforated like a sieve, so that it forms an almostcomplete sound-deadening wall.

Preferably, the perforations are not made of equal configuration but ofdifferent diameters, so as to provide satisfactory sound-deadeningcross-sections of the holes for all sound frequencies.

The sound-deadening eect of the walls is enhanced by providing twoco-axial cylinders, both of which are perforated, and by forming thebottom portion as a perforated plate.

To enhance the sound-deadening effect of the cup wall, air-permeableinserts of wadding, paper or the like may be placed in the cavitybetween the two cylinders and between the outer cylinder and the casing,and these should be replaced from time to time for hygienic purposes.

Good speech reproduction is sometimes distorted or impaired by speakingtoo loudly into the apparatus. When using the device, it is sufficientto speak with a subdued or soft voice, the strength of reception beingequally as loud as in normal conversation. In order to control theloudness when speaking into the mouthpiece, means are provided forcontrolling its audibility.

Application of the device for preventing overheing has a somewhatfatiguing effect, especially for long conversations. This causes thespeaker to fail to apply the mouthpiece with-sufficient firmness. Inaddition, there is the disadvantage that when the mouthpiece is used bydifferent persons, it is not hygienic unless it is cleaned after eachuse.

To remove these disadvantages, it was proposed to insert a paper cuphaving the form of the mouthpiece. It has now been found that paper cupscannot be easily fltilfltiA Patented Sept. 17, 1957 rice drawn orextruded in this form, and they are too expensive, especially for singleuse. It is therefore a further object of the invention to provide astamped out piece of paper of approximately oval shape. This piece ofpaper has a hole in the center and preferably a cardboard ring may beglued to it for reinforcement. Flexible crepe paper is preferablyemployed. The piece of paper can easily be inserted into the mouthpieceby hand, its outer edge being placed round the edge of the mouthpiece.

A soft crepe paper makes application to the mouth pleasantly soft andcomfortable, even during long conversations; and it is also unnecessaryto press the mouthpiece very tightly against the mouth in order to havea sufficient tight sealing.

Other features and advantages of the invention will be apparent from thefollowing description of a number of examples of embodiments and fromthe drawings in which:

Fig. l is a longitudinal section of a device according to the invention,the mouthpiece and microphone forming a structure independent of thetelephone receiver,

Fig. 2 is a side View partly in section showing the insert element,

Fig. 3 is a partial sectional view showing a detail of the mouthpiece,

Fig. 4 is a plan view of a protective paper sheet for the mouthpiece,

Fig. 5 is a section showing a modified form of the bottom of themouthpiece,

Fig. 6 is a longitudinal section of a modified device which is placed onthe mouthpiece of the ordinary telephone receiver, and

Fig. 7 is a cross section taken on line A-B of Fig. 6.

In the first embodiment (Figs. 1 to 5), 1 denotes the mouthpiece of theinsert element, which is inserted in the casing containing the inhalevalve 11 and the exhale valve 12, as well as the microphone diaphragm 8.Behind the exhale valve 12, spaced perforate discs 14 are diposed oneabove the other to form a sound-damping labyrinth 13. In front of themicrophone diaphragm, a diaphragm 2 is provided for preventing thebreath of the speaker from reaching the microphone 8.

According to the invention, the part of the insert element projectinginto the casing 4 is formed as a doublewalled perforated cylinder 1a and3, and the bottom 15 is a perforated plate, thereby avoiding undesirablereflections at these parts of the wall. The mouthpiece 1 can be made inone piece with its cylinder 1a, for example of Plexiglas, and thecylinder 3 may be securely mounted or detachable. Cylinders 1a and 3 mayalso be made as a separate cup 1. The outer cylinder 3 may also beformed in one piece with the mouthpiece cup 1, and the inner cylinder 1ais inserted in a fixed or replaceable position in the cup 1. Thepossibility of replacing or removing the cylinder 3 or 1a is for thepurpose of enabling better cleaning, for example in a liquid. Forcleaning, it is possible to use a small glass or plastic container ofappropriate size, containing a liquid for hygienic cleaning and having awell fitting cover which is ground in or has a rubber seal.

To avoid excessive loud speaking into the device, a small measuringinstrument 5, similar to a pressure gauge, is provided as shown inFig. 1. In the cup 1 is a hole 1b, through which the dammed up air orair pressure inside the cup is directed to a pressure gauge 5. The scalehas a red mark 5a and a pointer should not move beyond this mark orshould be deflected as far as that point to obtain good speechreproduction.

Fig. 3 shows another warning device operative on the acoustic principle.A whistle is mounted on the casing wall 4 but this whistle could also bemounted, for example, at the point where the hole 1b is situated (seeFig. l). The whistle consists of a tube 6 with a narrow air outletorifice 6a. The whistle cap 7 has an outlet orice 7a, as is usual inwhistles. The crosssections of the air outlet orifices 6a and 7a are sodimensioned that for a certain loudness or air pressure, a whistlingsound is produced, indicating that the user is speaking too loudly intothe mouthpiece. The whistle shown in Fig. 3 is representeddiagrammatically only since any note producing device known from theconstruction of musical instruments may be used for this purpose.

Fig. 4 shows a protective sheet of paper 9 which is placed in themouthpiece 1 for hygienic reasons. The paper, which may be made ofexible crepe paper, has a hole in the center surrounded by a cardboardring 10. The paper is held by the cardboard ring and easily inserted inthe mouthpiece 1 with one hand, and the outer edge of the paper placedround the edge, as shown in Fig. 2. The oval shape or stamping of thepaper adapts it to the shape of the oval mouthpiece 1.

Certain embodiments are proposed, wherein the device with thesound-tight mouthpiece is either pivoted to an ordinary telephonereceiver or is used connected in parallel to an exisiting normaltelephone receiver. In the latter case, therefore, the microphoneincorporated in the device is connected in parallel with the microphoneof the usual telephone receiver. With the microphone connected inparallel, the sound in the earpiece Vof the receiver is considerablyreduced during normal conversation. However, only the -earpiece of theusual telephone receiver can be used, and by suitably holding or placingthe earpiece against the ear, the mouthpiece of the device can bebrought to the mouth. The weakening of the microphone current is notthen perceptible as a drawback, or the same sound is obtained at theearpiece as during normal conversation.

In order to take into account the requirements for both cases, i. e. fornormal conversation or when using the device with the sound-tightmouthpiece, it is proposed to provide on the casing 4 a small buttonwhich can be pressed by the finger when holding the device. Themouthpiece 8 is switched on by means of the small button or electricswitch. When, therefore, the device is not used, i. e. the button is notpressed and only normal conversation is carried on, only the mouthpieceof the normal telephone receiver is switched on, so that noVdeterioration or weakening of the sound can occur in the receiver.Similar arrangements are usual in telephone apparatus provided with asecond earpiece. As a rule, the second earpiece carries a button, bymeans of which the earpiece is switched on, so that weakening of theloudness in the earpiece can occur only when the second earpiece isswitched on.

The push-button is not shown in Fig. l, since it is merely a matter of asimple step in switching technique.

In the secondrernbodiment (Figs. 6 and 7), the device is formed withouta mircophone, i. e. it is adapted to be placed on a usual telephonereceiver, with the sound damper 100 fast in the casing 101, and themouthpiece 102 with the perforated cylinder 102a is inserted intelescopic fashion. Furthermore, there is inserted in the mouthpiece 102a second perforated removable cylinder 103, which may be provided with aperforated bottom 103er. The perforated cylinders are designed linprinciple as in Fig. 1 with the sole difference that it is the innercylinder 103 which is replaceable, not the outer cylinder.

The mouthpiece 102 is pressed upward by a spring 104. During speech, themouthpiece assumes the optimum position by the pressure of the mouth,the earpiece of the telephone receiver also taking up the optimumposition relative to the ear. The resilient application of themouthpiece 102 against the mouth ensures that the application is alwaysuniform and that the hermetic il closure `is uniform and that no soundcan escape to the outside.

Interposed between the mouthpiece and the microphone of the telephonereceiver there is provided a diaphragm and a diaphragm 106, as well as aperforated plate 107. The perforated plate 107 also contributes inimproving speech reproduction and is necessitated by the size of thesound space 101a in the casing 101. The number of perforated cylindersand perforated discs, e. g. 102er, 103, 103a, 107 depends upon the sizeof the inner spaces of the mouthpiece and must be determined in eachcase by experiment. The diaphragm 108 on the cylinder 102er, as well asthe diaphragm 105 and 106 Serve for preventing speech moisture fromentering the microphone and sound damper. Apart from the diaphragm 108,it is also sutiicent if one of the diaphragms 105 and 106 is mounted inthe passage of the microphone. The drawing shows various possible waysof assembly. The parts 105, 106 and 107 may be mounted in a replaceablemanner.

I claim as my invention:

l. A telephone device comprising a cylindrical casing provided with amouthpiece adapted for enclosing the mouth of the conversing person in asoundproof manner, said casing having a sound-damping air-outlet for theair expired by the conversing person, an inlet valve to close anair-inlet opening during expiration of air by the conversing person andto permit the entry of air there through during the inspiration of airby the conversing person, an outlet valve insaid mouthpiece disposedbetween said sound-damping air outlet and said air inlet opening andoperative to prevent the ow of fair into said mouthpiece through saidoutlet during inspiration of air by the conversing person, amoisture-proof sound transmitting protective diaphragm interposedbetween the interior of said mouthpiece and a microphone, and a hollowinsert body in the mouthpiece having a flaring mouth-engaging portion atone end and a cylindrical portion adapted to be inserted into thecylindrical casing on the other end, the said cylindrical portionconsisting of two coaxial sievelike perforated cylindrical side-wallsand a bottom diaphragm portion.

2. A telephone device according to claim l, in which the microphone ismounted adjacent to and below the bottom diaphragm of the insert body.

3. A telephone device according to claim l, in which the insert bodyconsists of two coaxial perforated cylinders anda bottom portionconsisting of a perforated plate.

4. A telephone device according to claim l, in which a diaphragm coveredsieve plate is arranged adjacent the cylindrical walls of the insertbody and the microphone is provided in a sidehollow portion of thecasing which hollow side portion is closed by the said diaphragm coveredsieve plate.

5. A telehone device comprising a cylindrical casing provided with amouthpiece adapted for enclosing the mouth of the conversing person in asoundproof manner, said casing having an air inlet valve and asound-damping air-outlet for the air expired by the conversing person, ahollow insert body in the said mouthpiece having a flaringmouth-engaging portion at one end and a cylindrical portion adapted tobe inserted into the cylindrical casing on the other end, the saidcylindrical portion consisting-of two coaxial sieve-like perforatedcylindrical sidewalls, a microphone disposed below the said insert body,and separating means interposed between the interior of said mouthpieceand the microphone for preventing a direct impingement of the expiredair by the conversing person against the microphone.

6. A mouthpiece device according to claim 5 in which the mouthpieceformed as an insert element in the casing containing the exhale `andinhale valves, the insert element being mounted so as to be axially andresiliently movable in the casing.

(References on following page) References Cited in the file of thispatent UNITED STATES PATENTS Sherburne Nov. 15, 1910 Higuchi Mar. 26,1918 Van Houte Sept. 9, 1924 Gamoty Sept. 13, 1927 6 Siez et a1. Iuly 7,1942, Hart Aug. 5, 1947 Webb Ian. 13, 1953 Junghans July 10, 1956FOREIGN PATENTS Italy June 11, 1931

